The present invention relates to a pipe clamp, and more particularly to a pipe clamp for securing and fixing a pipe with a large diameter used for an oil pipe line, etc.
For example, when a pipe line is to be laid some distance from the ground, supporting members on which the pipes are mounted are erected on the ground, but pipe clamps are required to secure the pipes to said supporting members. Said pipe clamps, sometimes, serve the role of a pipe joint, which wrap up the coupling portion when the pipes are to be coupled. Such a connecting method is mainly used when concrete pipes or cast pipes are coupled. Furthermore, when some damage is found in a pipe after a pipe line is laid, and the pipe of the damaged pipe line is required to be replaced with a new pipe, the pipe clamps are used to secure the pipes, in which case the end portion of the new pipe and the end part of the installed pipe are abutted on each other, and two pipe clamps are used to secure the pipes by sandwiching the jointed part then, a full-circled welding is performed.
A typical example of the pipe clamp provided for such various practical purposes is shown in FIG. 1. The pipe clamp is composed of two semi-circular bands 11 and 12, and flanges 14 having ribs 13 are fixed to the outsides of the end portions of the bands 11 and 12 a plurality of holes for bolts are formed in the flanges 14. When the pipe clamp is used to fasten pipe, the bolts put through the holes in the opposed flanges 14 of the semi-circular bands 11 and 12 sandwiching the pipe and nuts are used to fasten and clamp said pipe.
However, to use a large number of bolts and nuts in clamping the pipe means that the clamping operation requires a lot of time and work, and when viewed from a standpoint of workability, it is by no means effective. As the diameter of pipe increases in its size, the number of divided sections of the pipe clamp increases, which will be more than two. Consequently, pipe clamp fastening portions are also increased accordingly in number and the workability goes from bad to worse. Furthermore, when the clamping has to be made at more than two portions, it becomes difficult to uniformly maintain the mutual clamping forces. That is, it is very difficult, from a practical of view, to maintain all the clamping forces uniform in the plural clamping portions of the pipe clamp by clamping operations using only bolts and nuts. Moreover, there are cases where a slippage results between the upper and lower bands due to some reason or another when the pipe clamp is being fastened or after the clamping is completed, but there is no provision for means of adjusting the slippage in the conventional pipe clamp.